HAI is working with industry partners to overturn, mitigate negative effects on GPS, radar altimeters.

Congress has been focused on passing pandemic aid packages and debating an infrastructure bill. However, we’re less than 90 days out from a possible government shutdown. Congress doesn’t seem too concerned; lawmakers seem already resigned to passing a continuing resolution (CR) to keep the government funded past September.

This is becoming a true talent. For over a decade, Congress has missed the Oct. 1 deadline and resorted to CRs to keep the government funded. Congress is particularly slow this year, so expect the CR punt to continue into December. Is it too soon to think about funding solutions as an early Christmas present?

While Congress tries to come to agreement on infrastructure, there are two important issues facing our industry: ­sustainability and spectrum. These issues can get highly technical, but bear with us. We hope by the end of this article, you’ll have a better understanding of how these issues could directly affect you—and what you can do to influence the outcome.


The environment and climate change are top priorities for the Biden administration, and the aviation industry has made significant investments in technology to enable the reduction of its greenhouse gas (GHG) emissions. This type of proactive action by our industry is important, as we can then target workable solutions instead of waiting for regulators to develop possibly overly burdensome regulations.

Per the report of the Intergovernmental Panel on Climate Change, it’s estimated that civil aviation contributes 2% of global CO2 and 3% of GHG emissions. The single largest potential reduction in aviation’s GHG emissions will come about through the broad adoption of sustainable aviation fuel (SAF). Produced from sustainable resources, SAF is a safe, approved substitute for Jet A or Jet A-1 and requires no changes to aircraft or fueling infrastructure. Compared with conventional jet fuel, SAF has the potential to reduce life-cycle GHG by up to 80%.

To help operators better understand SAF and its potential to reduce GHG emissions within the aviation sector, HAI is planning two HAI@Work webinars. The first, on Sep. 23, will provide operators with an understanding of the development, distribution, and usage of SAF. In the second webinar, scheduled for Sep. 30, representatives from the world’s leading helicopter and engine manufacturers will talk about efforts to promote the development and use of SAF. (HAI@Work webinars are held at 4:00 pm eastern time; register at rotor.org/webinar.)

HAI is also a member of the Business Aviation Coalition for Sustainable Aviation Fuel (www.​future​of​​sustainable​fuel.com) and collaborates with other stakeholders in promoting SAF. HAI members themselves, such as Airbus, Bell, Bristow Group, Safran, and Pratt & Whitney, have recently released press statements on the work their company is doing to further promote SAF.

On Capitol Hill, a broad coalition of aviation interests has worked with Congress to introduce the Sustainable Skies Act, which proposes a blender tax credit for SAF to incentivize the production and use of low-carbon SAF. The legislation would establish a tax credit of $1.50 to $2.00 per gallon for SAF that achieves at least a 50% reduction in life-cycle GHG emissions compared with conventional jet fuel, with the precise amount of the credit linked to the SAF’s GHG emissions performance.


HAI is also working on several issues related to the US government’s management of the electromagnetic spectrum, or more specifically, interference with the L band, which is used by GPS units and satellite communications, and the C band, which is used by radar altimeters.

For a little background, the electromagnetic spectrum describes a range of radiation that surrounds us. Most of this radiation is invisible to our eyes, although it also includes visible light from any source. Parts of that spectrum were an untapped resource for most of human history. However, many essential modern technologies, including telecommunications, utilize the spectrum.

Have you heard that land is a good investment because they’re not making any more of it? Well, that’s also true for spectrum—there’s a finite amount of it, and as we think of more and more ways to use it, including GPS, Wi-Fi, and cell phones, competition is fierce for room on that spectrum. In 2015, the Federal Communications Commission (FCC), which in the United States administers access to the spectrum, raised $44.9 billion by selling licenses for carriers to utilize the 1700 MHz and 2100 MHz blocks for mobile voice, data, and messaging services.

Recently, the FCC approved two controversial orders allowing cellular operations to expand in areas adjacent to spectrum vital to aviation. The first was granting a petition by Ligado Networks to build its cellular network next to GPS and satellite communications frequencies in the L band. The second, which we’ll discuss below, was to auction spectrum to existing cellular companies in the frequencies used for radar altimeters in the C band.

GPS and Air-to-Ground Communications

When the Ligado cellular network becomes operational, GPS will face interference primarily from the thousands of Ligado base stations (towers), and air-to-ground communications through satellites will face interference from millions of Ligado user terminals (handsets), as shown in the graphic below.

Ligado Networks Signals Will Interfere with GPS. The FCC approved Ligado Networks’ request to operate in portions of the spectrum adjacent to that used by the US global navigation satellite system (GNSS), known as the Global Positioning System (GPS). Independent testing shows that the much-stronger Ligado signal will cause interference with the GPS signal. False, delayed, or missing GPS data could lead to helicopter accidents.

Our industry is effectively getting hit twice by interference from Ligado: the towers could take out GPS, and the handsets could take out air-to-ground communications as pilots land and take off. Use of GPS is fundamental to the continued safe and effective operations of our industry, where false, missing, or delayed GPS data can result in a tragic accident. Disrupting communications during takeoffs and landings, which are critical phases of flight, could have similar consequences for flight safety.

Fourteen federal agencies—including the Department of Defense (DOD)—tried to intervene with the FCC to stop the approval of the Ligado plan. Disregarding all protests, the FCC proceeded with the plan, refusing to take full account of the diverse services in the L band that would be significantly impaired by interference, including those relied on by military, federal, and public safety users.

While the FCC is the lead agency for spectrum management, Congress is listening to arguments about ways to mitigate the risks imposed by the Ligado plan. In the National Defense Authorization Act for fiscal year 2021, Congress included language prohibiting the DOD from entering into contracts with companies whose operations would cause spectrum interference, unless the Secretary of Defense certified that such operations did not cause harmful interference. Furthermore, it required the operator of that network to pay for any damages to DOD GPS devices.

Sen. James Inhofe (R-Okla.) recently introduced the Recognizing and Ensuring Taxpayer Access to Infrastructure Necessary for GPS and Satellite Communications Act of 2021 (RETAIN Act) to address the cost impact of the Ligado Order on both the public and private sectors. The bill directs that the FCC Ligado Order shall not be effective until Ligado has reimbursed both the public and private sectors for the costs associated with the interference Ligado would cause.

You can read more about how HAI is working to highlight this threat to aviation safety in HAI Chair Stacy Sheard’s From the Board article; James Viola’s President’s Message; and In the Spotlight, in which Ryan Terry of Lockheed Martin discusses the implications of the Ligado deal for operators and pilots.

Radar Altimeters

Impaired performance by radar altimeters is also a clear safety concern for our industry. Since 2017, the aviation industry has consistently noted during the FCC rulemaking process that deployment of 5G networks in the C band may interfere with radar altimeters.

In April 2020, the Radio Technical Commission for Aeronautics (RTCA) formed a 5G task force to conduct a quantitative evaluation of radar altimeter performance regarding interference, as well as a detailed assessment of the risk of such interference occurring and impacting safety. This study used technical information supplied by the mobile wireless industry and radar altimeter manufacturers.

In a subsequent, October 2020 report, RTCA indicated that 5G networks operating in the C band pose a major risk for interference with radar altimeters on all types of civil aircraft. HAI, along with a large coalition of aviation organizations, petitioned the FCC to suspend allocation of C band spectrum to wireless companies, but this petition was denied.

The deployment of the 5G networks is expected to occur in December 2021. Without a reversal by the FCC, the aviation industry will bear the brunt of identifying—and paying for—the near- and long-term technical and operational solutions.

Helicopters are the category of aircraft most affected by 5G interference, and HAI is hard at work developing solutions and a path forward to blunt the effects of interference. John Shea, director of the Government Affairs team, is now the co-chair of the Technical Operations subgroup of the coalition, which is working to develop actionable mitigations to radar altimeter interference.

What You Can Do

As Congress gets more involved in the implications of FCC mismanagement of the spectrum, there is an important role you can play in advocating for our industry. This August, Congress will take its traditional month off for recess. Lawmakers will head home to visit with constituents—like you—and learn about issues important to those who voted them in.

The FCC actions that threaten dependable GPS and radar altimeter performance are a classic example of how decisions made by a government bureaucrat could turn your world upside down. It’s our job—HAI’s and yours—to explain that to our elected representatives. The more voices they hear from, the more they’ll pay attention, particularly when those voices are from the people they have sworn to represent.

Commit now to reach out to your elected officials. During the August recess, invite them to your place of business, give them a tour, and show them all you do for the community. Discuss with them the real-world consequences of bad public policy.

Don’t know where to start? Reach out to us at advocacy​​@​rotor​.org, and we’ll gladly help you plan and connect with your lawmakers for a visit, including providing talking points that represent HAI’s positions that will help our industry move ­forward.

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John Shea

John Shea

John Shea is VAI’s senior director of government affairs. He came to the association in 2019 from the National Association of State Aviation Officials (NASAO), where he was interim president in 2018 and lead government affairs representative since 2017. Previously, as a legislative staffer, John advised multiple members of Congress on transportation policy.

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